Is Your Domain on an Email Blacklist? How to Check and Get Removed

Being on an email blacklist can send your emails straight to spam, or get them rejected outright, and most businesses only find out when customers stop replying.

The good news is that most listings can be removed. The catch is that removal only lasts if you fix whatever caused it first. This guide explains how blacklists work, how to check yours, which listings actually matter, and how to get off them properly.

A blacklist (often called a blocklist) is a list of internet addresses or domain names that have been linked to spam. Email providers check these lists when deciding whether to trust an incoming message.

There are two main kinds:

• IP blacklists list the server an email was sent from.
• Domain blacklists list domain names that appear in spam, either as the sender or in links inside the message.

Knowing which kind you’re on matters, because the cause and the fix are different.

Free tools can check dozens of blacklists at once:

• MxToolbox Blacklist Check — enter your domain name or your mail server’s IP address.
• Spamhaus’s own lookup tool — worth checking separately, because Spamhaus is one of the most widely used lists.

To find the IP address your emails are sent from, open an email you’ve sent to a Gmail account, choose “Show original”, and look for the sending server near the top. My guide on how to check your email is set up correctly walks through this and the other free checks.

Don’t panic if a checker shows one or two red results. There are hundreds of blacklists, and many are small or rarely used. The ones that most affect delivery are:

• Spamhaus — used by a very large share of email systems. A listing here is serious.
• Barracuda — widely used by businesses that run Barracuda spam filters.
• SpamCop — listings usually expire on their own within a day or so once spam reports stop.
• Microsoft’s own blocklist — if only Outlook, Hotmail or Microsoft 365 users are rejecting your email, Microsoft may have blocked you directly.

One Spamhaus list, the PBL, lists home and dynamic internet connections that shouldn’t send email directly. If you send through Google Workspace, Microsoft 365 or your web host, this isn’t usually a problem, and you shouldn’t request removal.

Blacklists list you because something sent spam, or something that looked like it. Request removal without fixing the cause and you’ll usually be relisted within days, and some lists make removal harder each time. Common causes include:

• a hacked email account sending spam — see my guide on what to do if your business email is hacked
• a hacked or insecure website sending spam, or a contact form being abused to send spam
• an infected computer on your network
• emailing a bought or old list, which hits spam traps (addresses that exist only to catch spammers)
• shared hosting, where another customer on the same server caused the listing

Once the cause is fixed:

• Go to the blacklist’s own website. Each major list has its own removal process. Checkers such as MxToolbox link to them.
• Explain briefly and honestly what happened and what you’ve done to fix it.
• For Microsoft, use Microsoft’s own delisting portal for its business email service, or its sender support form for Outlook.com and Hotmail.
• If you’re on shared hosting, contact your host. They control the server and are usually best placed to request removal, or to move you to a clean one.
• Be patient. Removal can take anything from minutes to a few days, depending on the list.

Never pay a third party who promises guaranteed removal. Major blacklists don’t charge for removal, and some lists treat paid “delisting services” as a red flag. A small number of lists offer paid express removal of their own, but those listings usually expire for free anyway.

• Secure your accounts with strong, unique passwords and 2-step verification.
• Keep your website and its plugins updated, and protect contact forms from abuse.
• Only email people who’ve agreed to hear from you, and remove addresses that bounce.
• Set up SPF, DKIM and DMARC properly, so it’s clear which email really comes from you. My guide to SPF, DKIM and DMARC explains how they work.
• Check the main blacklists every few months, and after any security scare.

A blacklist listing is one of several reasons emails end up in spam. If you’re not listed but still having problems, my spam diagnostic checklist covers the other common causes.

If you’ve found a listing and aren’t sure what caused it, or you’ve been relisted after removal, I can investigate properly, fix the cause and handle the removal requests for you.

If you found out about a listing from a bounce message, why emails bounce explains the other codes you might see.

Need help fixing this?

I provide:

• Free initial assessment
• Clear explanation of the issue
• Fixed-price solutions
• UK-based support

If you’ve found a blacklist listing, I can track down the cause, fix it and handle the removal for you.